<template>
  <div class="app-container">
    <h2 style="text-align: center;">发布新课程</h2>
    <el-steps :active="1" process-status="wait" align-center style="margin-bottom: 40px;">
      <el-step title="填写课程基本信息"/>
      <el-step title="创建课程大纲"/>
      <el-step title="最终发布"/>
    </el-steps>

  <el-form label-width="120px">
    <el-form-item label="课程标题">
      <el-input v-model="courseInfo.title" placeholder=" 示例：机器学习项目课：从基础到搭建项目视频课程。专业名称注意大小写"/>
    </el-form-item>
    <!-- 所属分类 TODO -->
  <el-form-item label="课程分类">
    <el-select
      v-model="courseInfo.subjectParentId"
      placeholder="一级分类" @change="subjectLevelOneChanged">
      <el-option
        v-for="subject in subjectOneList"
        :key="subject.id"
        :label="subject.title"
        :value="subject.id"/>

    </el-select>

  <!-- 二级分类 -->
  <el-select v-model="courseInfo.subjectId" placeholder="二级分类">
    <el-option
      v-for="subject in subjectTwoList"
      :key="subject.id"
      :label="subject.title"
      :value="subject.id"/>
  </el-select>

  </el-form-item>
    <!-- 课程讲师 -->
  <el-form-item label="课程讲师">
    <el-select
      v-model="courseInfo.teacherId"
      placeholder="请选择">
      <el-option
        v-for="teacher in teacherList"
        :key="teacher.id"
        :label="teacher.name"
        :value="teacher.id"/>
    </el-select>
  </el-form-item>
    <el-form-item label="总课时">
      <el-input-number :min="0" v-model="courseInfo.lessonNum" controls-position="right" placeholder="请填写课程的总课时数"/>
    </el-form-item>
    <!-- 课程简介-->
    <el-form-item label="课程简介">
        <tinymce :height="300" v-model="courseInfo.description"/>
    </el-form-item>
    <!-- 课程封面-->
    <el-form-item label="课程封面">
      <el-upload
        :show-file-list="false"
        :on-success="handleAvatarSuccess"
        :before-upload="beforeAvatarUpload"
        :action="BASE_API+'/eduoss/fileoss'"
        class="avatar-uploader">
        <img :src="courseInfo.cover">
      </el-upload>

    </el-form-item>

    <el-form-item label="课程价格">
      <el-input-number :min="0" v-model="courseInfo.price" controls-position="right" placeholder="免费课程请设置为0元"/> 元
    </el-form-item>
    <el-form-item>
      <el-button :disabled="saveBtnDisabled" type="primary" @click="saveOrUpdate">保存并下一步</el-button>
    </el-form-item>
</el-form>
  </div>
</template>

<script>
import course from '@/api/edu/course'
import subject from '@/api/edu/subject'
import Tinymce from '@/components/Tinymce'  //引入组件
    export default {
        //声明组件
        components:{ Tinymce },
        data(){
            return {
                saveBtnDisabled:false,
                courseInfo:{
                  title: '',
                  subjectId: '',      //二级分类id
                  subjectParentId: '',   //一级分类id
                  teacherId: '',
                  lessonNum: 0,
                  description: '',
                  cover: '/static/01.jpg',
                  price: 0
                },
                courseId:'',
                BASE_API: process.env.BASE_API, // 接口API地址
                teacherList:[],  //封装所有讲师的数据
                subjectOneList:[],  //一级分类
                subjectTwoList:[]   //二级分类
            }
        },
        created(){
          //获取路由id值
          if(this.$route.params && this.$route.params.id) {
              this.courseId = this.$route.params.id
              //调用根据id查询课程的方法
              this.getInfo()

          } else {
              //初始化所有讲师
              this.getListTeacher()
              //初始化一级分类
              this.getOneSubject()
          }
        },
        methods:{
          //根据课程id查询
            getInfo() {
                course.getCourseInfoId(this.courseId)
                    .then(response => {
                        //在courseInfo课程基本信息，包含 一级分类id 和 二级分类id
                        this.courseInfo = response.data.courseInfoVo
                        //1 查询所有的分类，包含一级和二级
                        subject.getSubjectList()
                            .then(response => {
                                //2 获取所有一级分类
                                this.subjectOneList = response.data.list
                                //3 把所有的一级分类数组进行遍历，
                                for(var i=0;i<this.subjectOneList.length;i++) {
                                    //获取每个一级分类
                                    var oneSubject = this.subjectOneList[i]
                                    //比较当前courseInfo里面一级分类id和所有的一级分类id
                                    if(this.courseInfo.subjectParentId == oneSubject.id) {
                                        //获取一级分类所有的二级分类
                                        this.subjectTwoList = oneSubject.children
                                    }
                                }
                            })
                            //初始化所有讲师
                            this.getListTeacher()
                    })
            },
            //上传封面成功调用的方法
            handleAvatarSuccess(res, file){
              this.courseInfo.cover = res.data.url
            },
            //上传之前调用的方法
            beforeAvatarUpload(file){
              const isJPG = file.type === 'image/jpeg'
              const isLt2M = file.size / 1024 / 1024 < 2
              if (!isJPG) {
                this.$message.error('上传头像图片只能是 JPG 格式!')
              }
              if (!isLt2M) {
                this.$message.error('上传头像图片大小不能超过 2MB!')
              }
              return isJPG && isLt2M
            },
            //点击某个一级分类，触发change，显示对应的二级分类
            subjectLevelOneChanged(value){
              //value就是一级分类id值
              //遍历所有的分类，包含以及和二级
              for(var i=0; i<this.subjectOneList.length;i++){
                //每个一级分类
                var oneSubject = this.subjectOneList[i]
                //判断：所有一级分类id和点击一级分类id是否一样
                if(value == oneSubject.id){
                  //从一级分类中获取里面的所有的二级分类
                  this.subjectTwoList = oneSubject.children
                  //把二级分类id值清空
                  this.courseInfo.subjectId = ''
                }
              }
            },
            //查询所有的一级分类
            getOneSubject(){
              subject.getSubjectList()
                .then(response => {
                  this.subjectOneList = response.data.list
                })
            },

            //查询所有的讲师
            getListTeacher(){
              course.getListTeacher()
                .then(response => {
                  this.teacherList = response.data.items
                })
            },
            //添加课程
            addCourse(){
              course.addCourseInfo(this.courseInfo)
                .then(response => {
                  //提示信息
                  this.$message({
                      type: 'success',
                      message: '添加课程信息成功!'
                  });
                  //跳转到第二步
                  this.$router.push({path:'/course/chapter/'+response.data.courseId})
                })
            },
            //修改课程
            updateCourse(){
              course.updateCourseInfo(this.courseInfo)
                .then(response => {
                     //提示
                    this.$message({
                        type: 'success',
                        message: '修改课程信息成功!'
                    });
                    //跳转到第二步
                    this.$router.push({path:'/course/chapter/'+this.courseId})
                })
            },
            saveOrUpdate(){
              //判断添加还是修改
              if(!this.courseInfo.id) {
                  //添加
                  this.addCourse()
              } else {
                  this.updateCourse()
              }
            }
        }
    }
</script>

<style scoped>
.tinymce-container {
  line-height: 29px;
}
</style>
